Shutter Control Unit

The ShutterCU provides high precision control of the shutter
blade movement. Software command and hardware signal interfaces exist
to connect the system to the camera and/or instrument control H/W and S/W.

Interfaces

The Interface to the camera/instrument control system is based
on hardware control lines. Software command communication is also
possible (ASCII over RS232, see below).

Hardware control lines

Three lines exist (i) for shutter open/close operation, (ii) to indicate the
"shutter closed" status and (iii) any error condition. These lines are
accessible through the SubD9 connector labelled "Control".
Use of the status and error control
lines is optional.

Serial command line (use is optional)

Through the RS232 line (SubD9 connector labelled "RS232") a host
can take control to get status information, to
recover from error conditions and to redefine velocity profile
parameters. Commands exist of 2 ASCII characters and up to 3 parameters
(e.g. "ex 1000" for a 1000msec exposure).

The exposure start signal (falling edge) is continously polled by software.
The polling loop takes about 25µsec. This time delay sets the ultimate limit for the
shortest possible exposure. In addition the shortest possible exposure
puls is limited electronically to 300µsec.